Since the days of the colonists, in the Northern United States and Canada, maple syrup and related sugar products have been manufactured by tapping maple sap from hard maple trees (Acer Saccharinum) typically in late winter or early spring. Heat is then applied from an open fire or confined flame against the bottom of a vaporizer tank or tub within which the maple tree sap is placed to concentrate the sap and produce maple syrup.
Indeed, maple sap containing 2% to 3% sugar as it comes from the tree has no maple flavor and no color. The characteristic flavor and maple color result from the reactions that occur when the maple sap is evaporated and concentrated to the syrup form by boiling.
Typically, the maple sap is fed into an upwardly open flue pan supported over a wood or coal fire and collecting the concentrated maple syrup which failed to be evaporated by the evaporation process. Evaporators of every type are used to manufacture maple sugar, sorghum and similar types of syrup or sugar products.
Maple syrup sugar producers are typically individuals or families working in so-called “sugar shacks” sometimes with limited electrical power. Maple sap is typically carried from the maple tree to the sugar shack either by conventional methods using horses to carry the sap collected in buckets through the sometimes rugged terrain leading to the shack or through a more modern method using hydraulic lines fluidly coupled both to the maple tree at one end and to a collecting vessel adjacent the sugar shack.
When the more modem method using fluid tubes or lines is favored, the maple sap emanating from the trees, commonly referred to as maple water, is carried through the hydraulic line towards the sugar shack by gravity. Although a negative pressure or vacuum is created in the hydraulic line, the vacuum is used essentially for extracting the sap from the maple tree as opposed to being used for carrying the sap towards the sugar shack.
Accordingly, sugar shacks are typically located at a low level terrain relative to the trees being sapped. However, even in ideal situations wherein the sapped trees are all located above the sugar shack, there sometimes exists a situation wherein the hydraulic line, because of the rugged terrain, must travel at a level lower than that of the sugar shack.
Hence, in such situations, maintaining proper flow of the sugar water to the sugar shack becomes problematic. Accordingly, there exists a need for providing a suitable method of somehow pumping the maple water located at a level underneath a sugar shack to a level higher than the latter so that the sap collecting system may continue to use gravity to induce flow of the maple water towards the sugar shack.
Several types of mechanical pumping mechanisms for transferring fluid from a lower to a higher level are known and are in wide use. Two of the most common types of pumps are the so-called dynamic or momentum-change pumps and the so-called positive displacement pumps.
Dynamic pumps add momentum to a fluid by means of rapidly moving blades, fans or the like. As the fluid moves through open passages and discharges into a diffuser section, its momentum is increased and its velocity converted into an increased pressure. Dynamic pumps include rotodynamic or rotary type pumps such as axial flow, centrifugal or radial exit flow and mixed flow pumps. They also include so-called injector pumps, fluid activated types such as gas lift and hydraulic ram pumps and electromagnetic pumps.
Positive displacement pumps all generally have some types of moving boundary that forces fluid to move by volume changes. The fluid is admitted through an inlet into a cavity, which then closes, and the fluid is squeezed through an outlet. Common examples of positive displacement pumps include reciprocating and rotary types. Reciprocating types use a plunger, a piston or diaphragm as the moving boundary. Rotary types use one or more sliding vanes, helical screws, gears or the like.
Such conventional pumps require several moving components having a relatively large mass or density. These components are subject to relative large accelerations and frictions require costly and time-consuming maintenance and are also prone to wear and vibrations. Typically, they also require elaborate lubrication, cooling and control systems involving additional components. Also, they usually typically require some means for priming the system prior to effective operation and are subject to damage due to neglect by the operator.
Accordingly, they are not well-suited to being used in the specific context of maple sap hydraulic lines. They are also not suitable for many other types of contexts requiring a relatively simple yet effective means of locally increasing the level of a liquid in a hydraulic system subjected to a vacuum. Accordingly, there exists a need for a maple sap collecting line pumping system.